Band 7 SL Chemistry Notes and Diagrams
Organised by Topic (from 1 to 11)
Contents
1) Stoichiometry....................................................................................................................................2
2) Atomic Structure................................................................................................................................3
3) Periodicity..........................................................................................................................................5
4) Chemical Bonding and Structure.......................................................................................................8
5) Energetics and Thermochemistry....................................................................................................14
6) Chemical Kinetics.............................................................................................................................17
7) Equilibrium......................................................................................................................................21
8) Acids and Bases...............................................................................................................................24
9) Redox Reactions...............................................................................................................................28
10) Organic Chemistry.........................................................................................................................33
11) Measurement and Data Processing...............................................................................................40
,1) Stoichiometry
Avogadro's constant
- Number of atoms in one mole of a substance
Formula for the number of atoms
- Number of atoms = number of moles x 6.02x10 23
How to calculate number of moles
- Moles = mass divided by molar mass
Formula for concentration
- concentration (mol/dm3) = number of moles/volume (dm3)
Calculating the limiting reagent
- calculate the number of moles of the reactants
- divide this by the coefficient
- the species with the lower number of moles is the LR
Gas equation
- PV = nRT
- P: pressure (1.01 x 105 Pa)
- V: volume (m3)
- T: temperature (Kelvin, +273)
- R: 8.3145J/K/mol
- n: moles
Formula for molar mass using the gas equation
- M = nRT/PV
Molecular mass definition
- average mass of a molecule/mass of 1/12 of one atom of 12C (carbon isotope)
Empirical vs molecular formulas
- Empirical: most simple ratio
- Molecular: actual whole number ratio between the elements of the compound
Sublimation
- Solid to gas
Deposition
- Gas to solid
When do real gases deviate from ideal behaviour? (2)
- high pressures and low temperatures
, Deviation from ideal behaviour (high pressure)
- space between particles is reduced and volume of real gas is higher than predicted from
ideal gas law
- attractive forces strengthen as particles approach more closely
Assumptions of ideal gas law (2)
- volume of gas particles is negligible
- no attractive forces between particles
Deviation from ideal behaviour (low temperatures)
- lower kinetic energy increases the strength of inter-particle forces
Why do gases deviate from the ideal gas law at high pressures
- molecules have finite volume
Homogenous reaction definition
- all species are in the same state
Heterogenous reaction definition
- the species are in different states
Do individual components retain their individual chemical properties in a mixture?
- Yes
Determining the end-point
- a good titration result is one which gives consistent results within 0.1cm 3 of each other
Back titration
- returning to the end-point after it has passed
- unreacted excess is determined by a titration against a standard solution
Finding volume using STP (dm3)
- STP times moles
STP formula
- moles = volume (dm3) divided by 22.7
2) Atomic Structure
How can properties on an element be predicted?
- The periodic table shows regular periodic trends in properties
Continuous spectrum vs line spectrum
- continuous: radiation spread over all wavelengths (white light passed through a prism)
- line: radiation absorbed at specific wavelengths
Organised by Topic (from 1 to 11)
Contents
1) Stoichiometry....................................................................................................................................2
2) Atomic Structure................................................................................................................................3
3) Periodicity..........................................................................................................................................5
4) Chemical Bonding and Structure.......................................................................................................8
5) Energetics and Thermochemistry....................................................................................................14
6) Chemical Kinetics.............................................................................................................................17
7) Equilibrium......................................................................................................................................21
8) Acids and Bases...............................................................................................................................24
9) Redox Reactions...............................................................................................................................28
10) Organic Chemistry.........................................................................................................................33
11) Measurement and Data Processing...............................................................................................40
,1) Stoichiometry
Avogadro's constant
- Number of atoms in one mole of a substance
Formula for the number of atoms
- Number of atoms = number of moles x 6.02x10 23
How to calculate number of moles
- Moles = mass divided by molar mass
Formula for concentration
- concentration (mol/dm3) = number of moles/volume (dm3)
Calculating the limiting reagent
- calculate the number of moles of the reactants
- divide this by the coefficient
- the species with the lower number of moles is the LR
Gas equation
- PV = nRT
- P: pressure (1.01 x 105 Pa)
- V: volume (m3)
- T: temperature (Kelvin, +273)
- R: 8.3145J/K/mol
- n: moles
Formula for molar mass using the gas equation
- M = nRT/PV
Molecular mass definition
- average mass of a molecule/mass of 1/12 of one atom of 12C (carbon isotope)
Empirical vs molecular formulas
- Empirical: most simple ratio
- Molecular: actual whole number ratio between the elements of the compound
Sublimation
- Solid to gas
Deposition
- Gas to solid
When do real gases deviate from ideal behaviour? (2)
- high pressures and low temperatures
, Deviation from ideal behaviour (high pressure)
- space between particles is reduced and volume of real gas is higher than predicted from
ideal gas law
- attractive forces strengthen as particles approach more closely
Assumptions of ideal gas law (2)
- volume of gas particles is negligible
- no attractive forces between particles
Deviation from ideal behaviour (low temperatures)
- lower kinetic energy increases the strength of inter-particle forces
Why do gases deviate from the ideal gas law at high pressures
- molecules have finite volume
Homogenous reaction definition
- all species are in the same state
Heterogenous reaction definition
- the species are in different states
Do individual components retain their individual chemical properties in a mixture?
- Yes
Determining the end-point
- a good titration result is one which gives consistent results within 0.1cm 3 of each other
Back titration
- returning to the end-point after it has passed
- unreacted excess is determined by a titration against a standard solution
Finding volume using STP (dm3)
- STP times moles
STP formula
- moles = volume (dm3) divided by 22.7
2) Atomic Structure
How can properties on an element be predicted?
- The periodic table shows regular periodic trends in properties
Continuous spectrum vs line spectrum
- continuous: radiation spread over all wavelengths (white light passed through a prism)
- line: radiation absorbed at specific wavelengths
